Phys Ed: Can Exercise Make Kids Smarter?

By GRETCHEN REYNOLDS

In an experiment published last month, researchers recruited

schoolchildren, ages 9 and 10, who lived near the ChampaignUrbana campus of the University of Illinois and asked them torun on a treadmill. The researchers were hoping to learn moreabout how fitness affects the immature human brain. Animalstudies had already established that, when given access torunning wheels, baby rodents bulked up their brains,enlarging certain areas and subsequently outperformingsedentary pups on rodent intelligence tests. But studies of theeffect of exercise on the actual shape and function ofchildrens brains had not yet been tried.So the researchers sorted the children, based on their treadmill runs, into highest-,lowest- and median-fit categories. Only the most- and least-fit groups continued in thestudy (to provide the greatest contrast). Both groups completed a series of cognitivechallenges involving watching directional arrows on a computer screen and pushingcertain keys in order to test how well the children filter out unnecessary informationand attend to relevant cues. Finally, the childrens brains were scanned, using magneticresonance imaging technology to measure the volume of specific areas.Previous studies found that fitter kids generally scored better on such tests. And in thiscase, too, those children performed better on the tests. But the M.R.I.s provided aclearer picture of how it might work. They showed that fit children had significantlylarger basal ganglia, a key part of the brain that aids in maintaining attention andexecutive control, or the ability to coordinate actions and thoughts crisply. Since bothgroups of children had similar socioeconomic backgrounds, body mass index and othervariables, the researchers concluded that being fit had enlarged that portion of theirbrains.Meanwhile, in a separate, newly completed study by many of the sameresearchers at the University of Illinois, a second group of 9- and 10-year-oldchildren were also categorized by fitness levels and had their brains scanned,but they completed different tests, this time focusing on complex memory.Such thinking is associated with activity in the hippocampus, a structure inthe brains medial temporal lobes. Sure enough, the M.R.I. scans revealedthat the fittest children had heftier hippocampi.

The two studies did not directly overlap, but the researchers, in their separate reports,noted that the hippocampus and basal ganglia regions interact in the human brain,structurally and functionally. Together they allow some of the most intricate thinking.If exercise is responsible for increasing the size of these regions and strengthening theconnection between them, being fit may enhance neurocognition in young people, theauthors concluded.These findings arrive at an important time. For budgetary and administrative reasons,school boards are curtailing physical education, while on their own, children growincreasingly sluggish. Recent statistics from the Centers for Disease Control andPrevention show that roughly a quarter of children participate in zero physical activityoutside of school.At the same time, evidence accumulates about the positive impact of even smallamounts of aerobic activity. Past studies from the University of Illinois found that just20 minutes of walking before a test raised childrens scores, even if the children wereotherwise unfit or overweight, says Charles Hillman, a professor of kinesiology at theuniversity and the senior author of many of the recent studies.But its the neurological impact of sustained aerobic fitness in young people that isespecially compelling. A memorable years-long Swedish study published lastyear found that, among more than a million 18-year-old boys who joined the army,better fitness was correlated with higher I.Q.s, even among identical twins. The fitterthe twin, the higher his I.Q. The fittest of them were also more likely to go on tolucrative careers than the least fit, rendering them less likely, you would hope, to live intheir parents basements. No correlation was found between muscular strength andI.Q. scores. Theres no evidence that exercise leads to a higher I.Q., but the researcherssuspect that aerobic exercise, not strength training, produces specific growth factorsand proteins that stimulate the brain, said Georg Kuhn, a professor at the University ofGothenburg and the senior author of the study.But for now, the takeaway is clear. More aerobic exercise for young people, Mr. Kuhnsaid. Mr. Hillman agreed. So get kids moving, he added, and preferably away from theirWiis. A still-unpublished study from his lab compared the cognitive impact in youngpeople of 20 minutes of running on a treadmill with 20 minutes of playing sports-stylevideo games at a similar intensity. Running improved test scores immediatelyafterward. Playing video games did not.